Interlocking of mats having staggered elongated components

ABSTRACT

An interlockable industrial mat having a plurality of elongated members some of which are arranged in staggered orientation to form protrusions and corresponding recesses on opposite ends of the mat. The elongated members are held together by a plurality of joining; members. To facilitate interlocking of one mat with another similarly configured mat, each protrusion includes a first hole that is in alignment with a first bore for receiving a connecting rod, and each end of the non-staggered members is provided with a second hole that is in alignment with a second bore for receiving another same size rod. The first and second bores are in alignment such that when the protrusions of one mat are received in the recesses of another mat, a connecting rod can be passed through each bore to interlock the mats together. Multiple mats can be interlocked that way to form temporary support structures.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Application 62/770,255, filed Nov. 21, 2018, the entirety of which is herein incorporated by reference.

BACKGROUND

The present invention relates to industrial mats that include a plurality of elongated members fastened together in a staggered configuration that allows the end of one mat to be interlocked with the opposite end of a similarly configured mat. The interlocking of the mats is attained through the use of a connector rod that passes through holes or apertures in protruding portions of the elongated members.

One form of an industrial mat that utilizes a joined plurality of elongated members is known in the art as crane mats. These typically consist of a plurality of parallel, wooden timbers which have been secured together to form a rectangular mat. Such mats have been used to build runways or roads upon which a heavy piece of equipment such as a lifting crane or tractor may be driven. These mats, however, have not included any means to interconnect or lock the mats to one another.

Other industrial mats have included different interlocking mechanisms. Some of these simply have male extensions that are received in similarly configured female recesses so that the ends of adjacent mats can be simply inserted into each other. These are sometimes deficient because the connections are not held together and separation is possible.

There are additional industrial mats that are joined together using nails, pins or complicated connectors which take time and effort resulting in much higher labor costs to join or connect the mats and thereafter to disconnect the interconnected mats.

Accordingly, while such mat joining or connecting arrangements exist, there still remains a need for industrial mats that can be interconnected or interlocked together securely but without complicated connection means. The present invention now provides new industrial mat constructions that meet this need.

SUMMARY OF THE INVENTION

The invention now provides an industrial mat comprising a plurality of elongated members each having top, bottom and side surfaces, a rectangular or square cross section of dimensions of between about 2″ by about 2″ to about 16″ by about 16″, and a length of about 1 foot to about 60 feet, with each beam having about the same dimensions and length, and with all elongated members oriented parallel to each other with the top surfaces substantially in alignment to form a top surface for the mat and the bottom surfaces substantially alignment to form a bottom surface for the mat. A plurality of joining members pass through each elongated member to retain the elongated members in position and connected together to form the mat,

At least some of the elongated members are arranged in staggered orientation with respect to others, with each staggered elongated member positioned in the mat with a first end portion extending beyond a first end of an adjacent, non-staggered elongated component to form a protrusion on one end of the mat. A second, opposite end of each staggered elongated member has a second end a least a portion of which is does not extend to a second end of the adjacent, non-staggered elongated component to form a corresponding recess on the opposite end of the mat. The protrusions have a size and arrangement that conforms to that of the recesses so that the protrusions of one mat can be received within the recesses of a similarly configured and adjacently positioned additional mat to interlock the mats together for use.

Between 4 and 24 elongated members are typically present in the mat, wherein at least 2 to as many as 12 of which are staggered to provide the protrusions. Preferably, between 4 and 10 elongated members are present in the mat with at least 2 to as many as 5 being staggered to provide the protrusions.

Each elongated member also preferred has width and height dimensions that range from about 4″ by about 4″ to about 12″ by about 12 “and a length of about 1 foot to about 40 feet, with every other elongated component being staggered to provide the protrusions. These elongated members are made of a solid or layered construction of wood, plastic or elastomeric materials. Combinations of these materials can be used when a layered construction is provided.

The mat may also include metal plates configured and dimensioned to be no larger than the sides of the elongated members with the metal plates provided between at least some or all of the elongated members that are adjacently positioned.

Each protrusion advantageously extends by a length that is about the same as either the width or height dimension of the elongated member. In one embodiment, each protrusion is formed of at least 50% of the width and height dimensions of the elongated member so that a stepped arrangement is provided on the second end of the mat with each step configured for receiving a protrusion from the end portion of an adjacent mat to allow interlocking of end to end adjacently arranged mats.

In another embodiment, each elongated member has approximately the same width, height and length dimensions and additional features are provided to facilitate the interlocking of similarly configured mats. A first hole passing through the first end of each protrusion may be provided, with these holes being in alignment to form a first bore that is configured to receive a connecting rod that can pass through them. Also, a second hole passing through the second end of each non-staggered elongated member may be provided, with those holes being in alignment to form a second bore that is configured to receive the same connecting rod that can pass through them. Thus, the first and second bores are configured to be in alignment such that when the protrusions of one mat are received in the recesses of another mat, a connecting rod can be passed through each bore to interlock the mats together.

Each of the first and second holes are preferably arranged to pass through a center of each elongated member from one side to the other at its respective first or second end. At least one or more of the first and second holes can include internal threads to receive a threaded joining member. The joining members can be solid rods, threaded rods, or a bolting arrangement that includes bolts alone or bolts and nuts. If desired, the holes may be provided with a sleeve to assist in receiving the connecting rod therein. A single sleeve can be provided after the protrusions are received in the recesses and before the connecting rod is inserted.

An optional feature of the mat includes an end member that provides a non-staggered end of the mat. Two different end members are provided depending upon which end of the mat is to be squared off. Each comprises an elongated member having a first side that is relatively flat and an opposite side that engages an end of the mat. One end member has opposite side portions that are configured and dimensioned for positioning between the first end portions that form the protrusions on that end of the mat, while another end member has side portions that are configured and dimensioned to conform to and extend into the recesses on the opposite side of the mat. Thus, the forward end of the mats can be squared off with one end member and the opposite end of the mat can be squared off with the other end member.

Another optional feature is a metal cap that is configured and dimensioned to fit the protrusions of the staggered elongated members, the second ends of the non-staggered elongated members, or both to protect the protrusions and second ends from damage when one mat is being interlocked with the other or when transporting, installing or retrieving the mat. The metal cap typically includes openings that correspond to the holes of the protrusions or second ends of the elongated members.

The invention also provides a temporary structure comprising a plurality of mats as disclosed herein wherein the mats are connected by the protrusions of one mat being received in the recesses of another mat. When holes and bores are provided in full size protrusions, a connecting rod is positioned in each bore to interlock the mats together. The connecting rod is releasably connected to the elongated members so that upon removal of the connection member, the mats can be disengaged from being interlocked.

The connecting rod is preferably a solid cylindrical rod that optionally includes threads. The connecting rod typically has a head on one end that is larger than the first or second holes and a threaded opposite end to receive nuts thereon or to engage a threaded holes in one of the protrusions of the staggered elongated members or one of the second ends of the non-staggered elongated members. The connecting rod is often threaded at on opposite ends to receive nuts thereon or to engage threaded holes in the one of the protrusions of the staggered elongated members or one of the second ends of the non-staggered elongated members. In this arrangement, the connecting rod may be threaded throughout the entire length of the rod and nuts are provided for each end.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The invention is more fully appreciated upon a review of the appended drawing figure which illustrates the most preferred embodiments of the invention and wherein:

FIG. 1 is an illustration of a first embodiment of an industrial mat in accordance with the present invention which is releasably interlockable by a joining rod to one or more adjacently end-positioned and similarly configured mats;

FIG. 2 is an illustration of a second embodiment of an industrial mat in accordance with the present invention which has a stepped end structure that is releasably interlockable with one or more adjacently end-positioned and similarly configured mats;

FIG. 3 is a perspective view of an end member for squaring off the end of the mat of FIG. 1 that includes protrusions;

FIG. 4 is a perspective view of an end member for squaring off the end of the mat of FIG. 1 that includes recesses;

FIG. 5 is a perspective view of an end member for squaring off the end of the mat of FIG. 2 that includes protrusions;

FIG. 6 is a perspective view of an end member for squaring off the end of the mat of FIG. 2 that includes recesses; and.

FIG. 7 is a side view of the end member of FIG. 6.

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to an interlockable industrial mat having a plurality of elongated members with some of the members arranged in staggered orientation to form protrusions and corresponding recesses on opposite ends of the mat. The elongated members are held together by a plurality of joining members. To facilitate interlocking of one mat with another similarly configured mat, one ends of the mat is provided with a number of protruding portions or protrusions, while the opposite end is provided with a number of recesses that matingly receive the protruding portions or protrusions of the other end of a similarly configured mat.

In a first preferred embodiment, a stepped arrangement is provided on one end of the mat with the opposite end configured in effect with upside down steps that are received upon the stepped arrangement of the first end of a similarly configured adjacent mat.

In an alternative but also preferred embodiment, generally for smaller size mats, each elongated member has a protrusion that is formed from the full height and width of the elongated member at a first end thereof. These protrusions include a first hole that is in alignment with a first bore for receiving a connecting rod, and each end of the non-staggered members is provided with a second hole that is in alignment with a second bore for receiving the same size rod. The first and second bores are in alignment such that when the protrusions of one mat are received in the recesses of another mat, a connecting rod can be passed through each bore to interlock the mats together. Thus, multiple mats can be interlocked to form temporary support structures.

The size of the mats can vary from about 1 to about 10 feet wide and about 1 to about 60 feet long. Lighter duty mats would be about 1 to about 4 feet wide and about 1 to about 8 feet long, while heavier duty mats would be about 4 to about 12 feet wide and about 10 to about 40 feet long. The mats may be rectangular or square of any size at or it within those values and of any particular feet or inch dimensions. Particularly preferred rectangular sizes (approximate width and length) include 1′ by 2′, 2′ by 4′ or 6′, 3′ by 6′ or 8′, 4′ by 6′, 8′ or 10′, 6′ by 9′, 12′ or 16′, 8′ by 12′, 14′, 16′ or 20′, and 10′ by 16′, 20′, 24′, 30′ or 40′.

The term “substantially” is used for its ordinary meaning to indicate that the dimensions are not precise or exact. A skilled artisan can readily determine what tolerances are acceptable to provide a surface that is considered to be flat based upon the size of the elongated members and the type of service that the mat is expected to provide. There is no requirement that the elongated members be perfectly flush with each other along the top and bottom surfaces of the mat. Typically, the term “substantially” will mean that the top and bottom surfaces of the elongated members can vary by as much as a few inches depending upon the size of the mats although in the more preferred embodiments and for smaller mats the variance is less than 1 inch.

Additionally, all dimensions recited herein are approximate and can vary by as much as ±10% to in some case ±25%. In some situations, the term “about” is used to indicate this tolerance. And when the term “about” is used before reciting a range, it is understood that the term is applicable to each recited value in the range. Often, the craftsmanship and engineering procedures that are followed in construction of these mats minimize these tolerances as much as possible or industrially practical.

The invention contemplates the use of various components in the mat structure. Typically, elongated members of wood boards have been used and the term “elongated members” as used herein means structures that assimilate wood boards or are otherwise configured with rectangular cross sections and lengths which are preferably the full length of the mat. Shorter lengths of these structures can be used, however, as they are typically bolted or otherwise fastened together to form the mat. These elongated members are typically solid but they can be hollow tubular components which are optionally filled with other materials such as foams or particles. Less than full length elongated members can be used if desired and often are used when the mat is longer than 20 feet but full length boards for the entire length of the mat is preferred when possible. In general, these elongated members are made of wood, engineered wood, thermoplastics, thermosetting plastics or elastomers. When made of wood, oak or other hardwoods, pine or other softwoods, or mixtures thereof can be used.

The elongated members are typically joined together using any type of fastener. “Fastener” is defined herein as any hardware device that mechanically joins or affixes the elongated members together, including but not limited to bolts, screws, nails, rivets, rods, anchors or combinations thereof. These fasteners are generally elongated and typically include a head on one end and a structure on the other end that can be secured in place in or outside of the component to be joined. For example, the opposite end can include a pointed end and/or screw threads, or a nut, cap, clip, pin or other member that forms a larger portion that resists or prevents withdrawal of the fastener from the joined components. Typically, these devices have a circular or conical cross-section, but they can instead be oval, polygonal or any combination of circular and straight perimeters. A “removable fastener” is one that is attached in a way that it can be removed and reused, with typical examples including bolts and nuts, rod members with removable clips, end members or pins, or the like. Of course, preferred removable fasteners would have a body with a cylindrical threaded end to receive washers and nuts.

The elongated members would typically each have width and height dimensions of from about 3″ by about 3″ up to about 16″ by about 16″ and a length that corresponds to that of the mat. The elongated members can be rectangular or square in cross-section, with preferred square sizes of approximately 3″, 4″ 6″, 8″ 10″, 12″ or 16″ and preferred rectangular sizes (approximate height by width or width by height) of 3″ by 6″, 4″ by 8″, 4″ by 10″, 6″ by 9″, 6″ by 12″, 8″ by 10″, 8″ by 12″, 10″ by 12, 12″ by 16″. Of course, the height and width dimensions can vary to other dimensions if desired, but as a practical matter, the preferred sizes are typically made available for purchase or lease by customers. The lengths can also vary as desired with the elongated members being made of unitary pieces or made in joined sections. Lengths of 8′, 10′, 12′, 14′, 16′, 20′, 24′, 32′, 40′ or 60′ may be used. In some situations, the width and length of the mats may be dictated by shipping and lifting limitations.

The number of elongated members can be very dependent upon their size and the desired size of the mat. Typically, between 4 and 24 elongated members are present in the mat, with at least 2 to as many as 12 of which are staggered to provide the protrusions. Preferably, between 4 and 10 elongated members are present in the mat with at least 2 to as many as 5 being staggered to provide the protrusions. The number can be odd or even and generally the staggered members would alternate with non-staggered members in a one by one or 2 by 2 alternating arrangement. Alternating the staggered and non-staggered members results in a configuration that leads to optimum interlocking of adjacent mats.

When a stepped arrangement of alternating staggered and non-staggered members is used, the protruding end portion of each staggered member would preferably have a height or thickness that is at least one half of the overall height of the member. While other fractional portions can be used, the one-half amount has been found to be useful and easy to implement. If desired, however, fractional thicknesses of between one quarter and three quarters of the height can be used. For convenience, the entire width of the elongated member is used but a skilled artisan would appreciate that portions of the width can remain on or be removed from any particular member on one end of the mat provided that the same complementary arrangement is provided on the opposite end so that adjacently arranged mats can be interlocked together. And although a rectangular stepped arrangement is shown, other configurations are possible on although they are generally more complicated to provide when preparing the ends of the elongated members.

A preferred arrangement is to utilize the full height and width of the elongated member as the protruding member, as that simply requires the staggered members to be offset by a particular distance with respect to the adjacent non-staggered members which of course are simply longitudinal members having ends that do not require any special finishing. The use of the same elongated members without the previously described step structures on the ends also simplifies the construction because it does not require any cutting or beveling operations to form the steps on the ends of the staggered members. For this embodiment, the protrusions would generally have a stick-out length of at least about ⅓ of the width or height of the elongated member up to about double that dimension. For example, for larger mats using elongated members that are between 8″ and 12″ in height and/or width, a stick-out of at least 4″ to as much as 12″ to 16″ would be used. For smaller mats and elongated members, those having a height and/or width of between 4″ and 6″, a stick-out of at least 2″ to as much as 6″ to 8″ are suitable. It is often convenient to provide a stick out that is the same as in distance as either the height or width of the member. For example for an 8″×8″ member, the stick out would be 8 inches. Routine tests can be conducted if necessary to determine the optimum stick-out dimension for any particular size elongated members or mat.

In the most preferred mats, each of the elongated members would have the same dimensions, and each other one would be staggered. And all protrusions would be of the same length so that the recesses are also of the same dimensions. For this embodiment, even if the protrusions are of different lengths, this would not be an issue because they automatically provide recesses of corresponding dimensions on the opposite end of the mat which of course would facilitate the joining and interlocking of the mats.

The elongated members can be made of many different materials, including wood, engineered wood, any conventional polymeric or copolymeric thermoplastic materials, thermosetting materials, or even fiberboard materials made of recycled plastic or polymeric materials from used carpets, plastic packaging and the like. The elongated members may also be made of elastomeric materials which can be thermosets (requiring vulcanization) or thermoplastic.

Any type of engineered or virgin wood can be used for the elongated members and this would typically include softwoods such as pine, hardwoods such as oak or mixed softwoods and/or hardwoods. The wood members of the mat that are to experience abuse or wear are preferably made of hardwoods such as white oak, red oak, beech, hickory, pecan, ash or combinations thereof. Also, engineered wood materials as described herein can instead be used. And in certain embodiments, softwoods such as pine, cedar other conifer tree materials can be used with pine preferred because it is a lower cost, readily available wood material.

As softwoods are not as abrasion and abuse resistant as hardwoods, the invention contemplates using the softwoods in combination with reinforcing metal plates. These plates, typically of steel or aluminum, can extend to the upper or lower surfaces of the mat and are covered by the upper and lower elongated members. In a mat where, for example, the softwood elongated members have a height of about 8″, a steel plate of similar height would be use. The plate is more resistant to abuse than the pine and protects it for a longer service life in the mat. Also, instead of metal, reinforced thermosetting plastics can be used with similar results. These reinforcing plates are also desirable for use with non-wood elongated members.

In the usual arrangement, the elongated members are solid generally rectangular structures, preferably of square cross-section, but in particular for the non-wood structures it is also possible to use hollow or filled rectangular elongated tubes depending upon the strength of the material used. Alternatively, the square structures can be made of a plurality of rectangular sheet or plate members that are joined together with by the joining members, by adhesives or by welding. When a stepped structure is provided, the plates would take the same side shape as the stepped staggered members.

A wide range of thermoplastic or polymeric materials can be used for the elongated members of this invention. These materials would be molded or cast to the desired size and thickness of the mat or can be provided in thinner layers that when combined achieve the desired overall dimensions of the elongated members. Useful materials include:

-   -   Acrylonitrile butadiene styrene (ABS)     -   Acrylic (PMA)     -   Celluloid     -   Cellulose acetate     -   Cyclo olefin Copolymer (COC)     -   Ethylene-Vinyl Acetate (EVA)     -   Ethylene vinyl alcohol (EVOH)     -   Fluoroplastics (PTFE, alongside with IBP, PFA, CTFE, ECTFE,         ETFE)     -   Ionomers     -   Kydex, a trademarked acrylic/PVC alloy     -   Liquid Crystal Polymer (LCP)     -   Polyacetal (POM or Acetal)     -   Polyacrylates (Acrylic)     -   Polyacrylonitrile (PAN or Acrylonitrile)     -   Polyamide (PA or Nylon)     -   Polyamide-imide (PAI)     -   Polyaryletherketone (PAEK or Ketone)     -   Polybutadiene (PBD)     -   Polybutylene (PB)     -   Polybutylene terephthalate (PBT)     -   Polycaprolactone (PCI)     -   Polychlorotrifluoroethylene (PCTFE)     -   Polyethylene terephthalate (PET)     -   Polycyclohexylene dimethylene terephthalate (PC (PC)T)     -   Polycarbonate     -   Polyhydroxyalkanoates (PHAs)     -   Polyketone (PK)     -   Polyethylene (PE)     -   Polyetheretherketone (PEEK)     -   Polyetherketoneketone (PEKK)     -   Polyetherimide (PEI)     -   Polyethersulfone (PES)—see Polysulfone     -   Polyethylenechlorinates (PEC)     -   Polyimide (PI)     -   Polylactic acid (PLA)     -   Polymethylpentene (PMP)     -   Polyphenylene oxide (PPO)     -   Polyphenylene sulfide (PPS)     -   Polyphthalamide (PPA)     -   Polypropylene (PP)     -   Polystyrene (PS)     -   Polysulfone (PSU)     -   Polytrimethylene terephthalate (PTT)     -   Polyurethane (PU)     -   Polysulfone (PSU)     -   Polytrimethylene terephthalate (PTT)     -   Polyvinyl chloride (PVC)     -   Polyvinylidene chloride (PVDC)     -   Styrene-acrylonitrile (SAN)

It is also possible to utilize fiberboard as the elongated members or sheets to form the elongated members. The fiberboard material is made of recycled plastic or polymeric materials from used carpets, plastic packaging and the like. In addition to being environmentally resistant due to their plastic content, these fiber boards are environmentally friendly by allowing recycling of used materials that contain plastic or polymeric materials.

The elongated members may also be made of an elastomeric material. The elastomers are usually thermosets (requiring vulcanization) but may also be thermoplastic. Typical elastomers include:

Unsaturated rubbers that can be cured by sulfur vulcanization—these are preferred from a strength and hardness standpoint:

-   -   Natural polyisoprene: cis-1,4-polyisoprene natural rubber and         trans-1,4 polyisoprene gutta-percha;     -   Synthetic polyisoprene;     -   Polybutadiene;     -   Chloropene rubber, i.e., polychloroprene;     -   Butyl rubber (i.e., copolymer of isobutylene and isoprene)         including halogenated butyl rubbers (chloro butyl rubber; bromo         butyl rubber);     -   Styrene-butadiene Rubber (copolymer of styrene and butadiene);         and     -   Nitrile rubber (copolymer of butadiene and acrylonitrile).     -   Saturated (i.e., non-vulcanizable) rubbers include:     -   Ethylene propylene rubber (EPM);     -   Ethylene propylene diene rubber (EPDM);     -   Epichlorohydrin rubber;     -   Polyacrylic rubber;     -   Silicone rubber;     -   Fluorosilicone Rubber;     -   Fluoroelastomers;     -   Perfluoroelastomers;     -   Polyether block amides; and     -   Chlorosulfonated polyethylene.

The elastomeric, thermoplastic or thermosetting materials disclosed herein can also be provided with conventional fillers to increase weight and hardness. They also can be reinforced with particulates, fibers such as glass, fabric or metal screening or scrim to reduce elongation and provide greater rigidity.

When multiple layers are used, the layers can be joined together by welding or adhesives but it also is acceptable to hold the layers together by providing additional joining members in the mat structure to hold the layers together along with holding the elongated members together in the mat.

As also noted, these materials can be made in the form of rectangular tubular shapes. When reinforced thermosetting or vulcanized elastomeric tubular shapes are provided, they typically possess the desired strength and rigidity for use in the mats of the invention. Additionally, the tubular shapes can be filled with a variety of different materials include foam, inorganic particulate matter, crumb rubber from recycled vehicle tires, or even sand or gravel to strengthen the mat.

The provision of protrusions and recesses in the mats of the invention enables a plurality of similarly configured mats to be inserted end to end with the protrusions of one mat placed in the recesses of an adjacent mat and then being interlocked into position by the insertion of a connecting rod for each pair of joined mats. This enables the interlocked mats to form a temporary surface or substrate upon which equipment can be moved or placed thereon.

For a more secure connection that may be required for holding the interlocked mats together, holes are provided through the protruding portions for receipt of joining or connecting rods that are temporarily placed in the holes to prevent movement or disengagement of the staggered protrusions from the recesses.

The sizes of the joining or connecting rods would be determined based on the overall sizes of the elongated members and mats. The cross-sectional size of the rods can be polygonal, oval or round with round being preferred. For smaller mats, cylindrical rods or bolting having a diameter of about ¼″ is acceptable while for larger members and mats, a diameter of ½ to as much as 1″ may be used. Routine testing can be conducted to determine the optimum rod or bolt size depending upon the construction and size of the elongated members and mats. This is also true for the selection of the number of joining members to use used. Typically at least one joining rod is used for every 2 to 3 feet of mat length.

The holes that are provided in the protrusions of the staggered elongated members or the second ends of the non-staggered elongated members would be slightly greater than the diameter or perimeter of the rod members to facilitate the smooth insertion of the rods through the bores and holes. Of course, the holes must be smaller than the rod or bolting heads and nuts. And for the embodiments where threads are provided on the protrusions or second ends of the respective elongated members, these would typically be provided only on the last or outermost elongated member to facilitate insertion of the rod at the opposite side of the mat and to engage the threaded hole only after the rod has passed through the holes of all other elongated members.

For sonic embodiments, the holes can be provided with an internal sleeve of plastic or metal to assist in allowing the rods to pass therethrough. Of course, the holes would need to be made larger than the rods to accommodate the sleeves therein while still providing a sufficient opening to receive and allow smooth travel of the rod therethrough. In other embodiments, a full length sleeve can be inserted prior to inserting the connecting rod.

And wherein one of the joining rods that is used to connect the elongated members together is exposed to allow lifting of the mat, the exposed portion of the rode would be located. sufficiently back in the recess so that there is room for the protrusion to properly enter the recess. In effect, a longer recess is provided so that there is additional space to expose the joining rod to facilitate grasping by the hook of heavy equipment to allow lifting and manipulation of the mats for loading for shipment or for installation or reclamation of the mats at a jobsite. The protrusion would terminate just in front of the exposed rod.

Turning now to the drawings, FIG. 1 illustrates the preferred embodiment where each of the elongated members is of the same size and configuration. The mat 100 is made of five elongated members 105, 110, 115, 120, 125. Elongated Members 110, 120 are staggered from other elongated members 105, 115, 125, and have ends 112, 122 that protrude beyond the ends of members 105, 115, 125. These ends 112, 122 include apertures or holes therein 114, 124 which pass completely through each protrusion from one side to the other at a generally central location. The opposite ends of each protrusion form a correspondingly shaped recess 113, 123 on the opposite end of the mat.

Members 105, 115, 125 on the opposite end of the mat have ends 107, 117, 127 that extend beyond the ends of the staggered members 110, 122 to form the end boundaries of the recesses. These members 107, 117, 127 each include a hole or aperture 109, 119, 129 therein that passes completely through the ends of those members from one side to the other at a generally central location.

The elongated members 105, 110, 115, 120, 125 are fixed in position by three joining rods 131, 133, 136 that pass completely through each member and which are secured on the opposite side by nuts 132, 135, 138.

The protrusions 112, 122 are configured with the holes or apertures 114, 124 in alignment to form a bore that receives a connecting rod 140 therein. When the opposite end of a similarly configured mat is placed within the recesses of this mat 100 thus engaging the protrusions 112, 122, the connecting rod 140 will pass through the holes of the three ends of the members of the other mat as well as through the holes in the two protrusions to connect and interlock the mats together. The joining rod 140 is secured at the opposite side of the mat by nut 145 to maintain the elongated members connected together.

On the opposite end of mat 100, the protrusions of a similarly configured mat can be received in recesses 113, 123, 129. Another connecting rod 150 can then be used to pass through the holes 109, 119, 129 of elongated members 105, 115, 125 and through the holes in the protrusions of the other mat. The connecting rod 150 would pass completely through the bore that is formed by the alignment of the holes of all five elongated members, and would be secured on the other side of the mat by engagement of nut 155.

This connection can be repeated for a number of mats to join them together add form a temporary walkway, roadway, decking or other flat surface upon wet or irregular terrain.

Another feature of the invention is the provision of an end cap 160 which is made in the form of an open metal box having two openings 162, 164 on opposite sides of the box. The 160 metal box of the end cap can slide over the end the protrusion 112 so that the apertures 162, 164 are in alignment with hole 114. The metal construction of the end cap 160 would protect the protruding portion from damage when the mats are moved or when they are positioned for interlocking with an adjacent similarly configured mat. A further end cap would also be provided for protrusion 122 as well as for the ends of the non-staggered elongated members on the opposite side of the mat.

FIG. 2 illustrates an alternative embodiment of the invention where the mat 200 includes a stepped arrangement on each end. Where like components from FIG. 1 are used, the same reference numbers are used.

Mat 200 includes five elongated members that are joined together with joining rods in the same manner as in FIG. 1. As shown, two of these elongated members 110, 120 have flat or unmodified ends. The three additional elongated members 205, 215, 225 that are provided in the mat are configured with ends that are prepared to form a step arrangement. The staggered and non-staggered members alternate in the mat. One end of elongated members 205, 215, 225 has lower protrusions 255, 265, 275 which are approximately one half the height of the elongated member. The bottom surfaces of these protrusions and the remainder of the elongated members 205, 215, 225 form the bottom surface of the mat 200. On the opposite end of these elongated members 205, 215, 225, upper protrusions 250, 260, 270 which are approximately one half the height of the elongated member are provided. The top surfaces of these protrusions 250, 260, 270 and the remainder of the elongated members 205, 215, 225 form the top surface of the mat 200. Therefore, after one mat is installed in position, an adjacent, similarly configured mat can be placed with protrusions 250, 216, 270 sitting upon protrusions 255, 265, 275 so that the mats can interlock and join together forming a continuous upper surface.

And if desired, an element configured like the opposite end including steps 255, 265, 275 and protrusions from elongated members 110, 120, but having a length that is no greater than the length of the protrusions, can be provided as a separate member to support protrusions 250, 216, 270 on the opposite side of the mat.

The ends of the mat may be squared off by the use of end members 300, 400 depending upon which end of the mat is to be squared off. End member 300, as shown in FIG. 3, is configured and dimensioned to square off the end of mat 100 of FIG. 1 that has protrusions 112, 122. End member 300 includes a flat forward end 310 with a flat upper surface 315 and a flat lower surface so that the mat 100 is provided with a rectangular forward end. End member 300 has protrusions 320, 325, 330 that are configured and dimensions to fit between and around ends 112, 122 of mat 100. Protrusions 320, 325, 300 also include apertures or holes therein 323, 328, 333 which pass completely through each protrusion in alignment with the apertures 114, 124 of protrusions 112, 122 of mat 100. Thus, when the protrusions 320, 325, 330 of end member 300 are placed within the recesses between protrusions 112, 122 of mat 100, the connecting rod 140 will pass through the holes 323, 328, 333 of the protrusions 320, 325, 330 of the end member 300 as well as through the holes 114, 124 of the two protrusions 112, 122 of the mat 100 to connect and interlock the end member 300 to mat 100. And the joining rod 140 can be secured by a nut or by being configured with threads that mate with threads in the holes 114, 124, 323, 328, 333 of the protrusions to maintain the end member 300 connected to the mat 100.

End member 400 includes a flat rearward end 410 with a flat upper surface 415 and a flat lower surface so that the mat 100 is provided with a rectangular rearward end. End member 400 has protrusions 420, 425 that are configured and dimensions to fit in the recesses 113, 123 of the opposite end of mat 100. Protrusions 420, 425 also include apertures or holes therein 423, 428 which pass completely through each protrusion in alignment with the apertures 109, 119, 129 of protrusions 107, 117, 127 of mat 100. Thus, when the protrusions 420, 425 of end member 400 are placed within the recesses 113, 123 between protrusions 107, 117, 127 of mat 100, the connecting rod 150 will pass through the holes 423, 428 of the protrusions 420, 425 of the end member 400 as well as through the holes 109, 119, 129 of the three protrusions 107, 117, 127 of the mat 100 to connect and interlock the end member 400 to mat 100. And the joining rod 150 can be secured by a nut or by being configured with threads that mate with threads in the holes 109, 119, 129, 423, 428 of the protrusions to maintain the end member 400 connected to the mat 100.

When a number of mats are joined together to form a covering surface or platform, a number of end members 300 can be used on the forward ends of the mats in the covering surface or platform. Additionally, the opposite end of the surface or platform can be provided with end members 400 for each mat. By these combinations, the covering surface or platform will have squared off ends on the forward and rearward ends.

Similarly, end members 500, 600 can be provided for squaring off the forward and rearward ends of mat 200 of FIG. 2. End member 500, as shown in FIG. 5, is configured and dimensioned to square off the forward end of mat 200 of FIG. 2 that has the two elongated members 110, 120 that have flat or unmodified ends. End member 500 includes a flat forward end 510 with a flat upper surface 515 and a flat lower surface so that the mat 200 is provided with a rectangular forward end. End member 500 is configured and dimensioned with protrusions 520, 525, 530 that fit onto the steps of the lower protrusions 255, 265, 275 of the elongated members 205, 215, 225 of mat 200. As one end of elongated members 205, 215, 225 are approximately one half the height of the elongated member, the protrusions 520, 525, 530 also have one half the height of the elongated member so that when the end member 500 is placed upon mat 100, a squared end of uniform thickness is provided.

End member 600, as shown in FIG. 6, is configured and dimensioned to square off the rearward end of mat 200 of FIG. 2 that has the three protrusions 250, 260, 270. End member 600 includes a flat forward end 610 with a flat upper surface 615 and a flat lower surface so that the mat 200 is provided with a rectangular rearward end. End member 600 is configured and. dimensioned with protrusions 620, 625 that fit below the protrusions 250, 260, 270 of mat 200. As one end of protrusions 250, 260, 270 are approximately one half the height of the elongated member and positioned in an upper portion of the mat, the end member 600 protrusions 620, 625 630 also have one half the height of the elongated member and are positioned in a lower portion of the mat so that when the end member 600 is placed under protrusions 250, 260 270 of mat 200, a squared end of uniform thickness is provided.

The wood, plastic and elastomeric materials disclosed herein generally have sufficient strength for many applications, but their strength and rigidity can be enhanced by reinforcing the elongated members with a metal plate that is provided in the same height and length as the elongated member and that is preferably included between each paid of adjacent elongated members. These plates which may be made of steel or aluminum, reinforce the mat and assist in strengthening and protecting the elongated members. They also allow softwoods such as pine to be used by helping protect the elongated members from abuse because the plate provide structures between each elongated member that are much more rigid and resistant to damage. These plates would have the same configuration as the side of the elongated member next to which they are positioned.

In some embodiments where the mat materials are made of plastic and are not sufficiently resistant to withstand long term exposure to sunlight, appropriate additives to improve the UV resistance of the material can be included. The materials used for the elongated members mats can provided with various types of known reinforcements for different applications.

Another aspect of the invention relates to the providing of each mat with identification means that indicates the material, reinforcement and construction of the elongated members. Thus, when a number of mats made of different elongated members are maintained in an inventory, the identification means enables operators to readily determine which mats have the particular materials and properties needed for a particular end use, so that the correct mats can be selected and provided to a jobsite for use by the customer. This would be necessary whether the mats are being purchased by the customer or whether the mats are being leased for use.

There are a number of ways to identify the different materials and properties of a mat depending upon the specific type of identification means that are applied to the mat. The preferred types of identification means include an external color code, a radio frequency identification (RFID) tag, or an alphanumeric indicator applied to an outer surface of the mat or that is provided upon a plate that is applied to an outer surface of the mat. The simplest identification means to use is an external color code that is placed upon the mat, preferably in an area that does not receive much abrasion or wear. Different colors or strips or color combinations can be used to identify different materials. And it is highly useful to apply the color code to the same relative positions on each mat for easy identification. For example, placing the external color code along a longitudinal side of each mat allows the color coding to be visible when the mats are stacked upon each other. This simple visual confirmation can be used to make sure that the proper mats are selected: even when the mats are just stacked in the work yard, one can see which ones have the correct color code for the desired core construction.

Another use of color can be to identify certain panel mats that are to be used only by a particular customer. This would assist in making sure that the mats are properly collected and delivered. This color can be an additional color beyond that which is used to identify the mat core, or the mats can have a single unique color or color pattern (e.g., stripes, dots etc.) that identifies both the customer and the mat core. And further, the color can be provided in a particular location or area to confirm who the customer is to assist in quality control regarding the correct shipping and delivery of the mats.

A simpler type of identification means is one that comprises an external alphanumeric indicator that is applied to an outer surface of the mat or that is provided upon a plate that is applied to an outer surface of the mat. These can be carved, burnished or stamped into or onto the mat again is a location that is not expected to experience severe abrasion or wear. This can also be used to identify a particular customer.

And as noted herein, in addition to the mat identification means, each mat can further be provided with a surface color that indicates a potential use or non-use of the mat. This can assist in allowing personnel to properly operate on the mat and to promote safety. These colors can include, for example, red to indicate that portions of the mat need to be kept free of equipment, yellow for indicating that caution is needed, green to indicate portions of the mat that are designed to accommodate travel or movement by trucks or heavy equipment over the mat.

Of course other colors can be used in any of the foregoing embodiments according to a particular code or correspondence of each color to a specific use or prohibited use. These colors can be tailored to the mat user's particular requirements so that work operations upon or around the mats can be optimized for safety, efficiency and expediency. Coloring can also be used to define certain areas of the worksite or to help the mats blend into surrounding areas, so that the jobsite can look as clean and undisturbed as possible. For these reasons the use of conventional paints and other surface coatings enhance the usefulness of the mats for any particular application. These paints or coatings would need to be compatible to bond with the materials of the mat. If necessary, appropriate primers or other chemicals can be used to assure strong bonding of the paints or coatings to the mats.

Therefore, in sum, it is to be realized that the optimum dimensional relationships for the parts of the invention can include variations and tolerances in size, materials, shape, form, function and use are deemed readily apparent and obvious to the skilled artisan, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the claims appended hereto.

Unless defined otherwise, all technical and scientific terms used herein have same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Also, as used herein and in the appended claims, the singular form “a”, “and”, and “the” include plural referents unless the context clearly dictates otherwise. All technical and scientific terms used herein have the same meaning.

The foregoing detailed description is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily be apparent to those having ordinary skill in the art, it is not desired to limit the invention to the exact constructions demonstrated. Accordingly, all suitable modifications and equivalents may be resorted to falling within the scope of the invention, 

What is claimed is:
 1. An industrial mat comprising: a plurality of elongated members each having top, bottom and side surfaces, a rectangular or square cross section of dimensions of between about 2″ by about 2″ to about 16″ by about 16″, and a length of about 1 foot to about 60 feet, with each beam having about the same dimensions and length, and with all elongated members oriented parallel to each other with the top surfaces substantially in alignment to form a top surface for the mat and the bottom surfaces substantially in alignment to form a bottom surface for the mat; and a plurality of joining members passing through each elongated member to retain the elongated members in position and connected together to form the mat; wherein at least some of the elongated members are arranged in staggered orientation with respect to others, with each staggered elongated member positioned in the mat with a first end portion extending beyond a first end of an adjacent, non-staggered elongated component to form a protrusion on one end of the mat, and with a second, opposite end of each staggered elongated member having a second end a least a portion of which is does not extend to a second end of the adjacent, non-staggered elongated component to form a corresponding recess on the opposite end of the mat, with the protrusions having a size and arrangement that conforms to that of the recesses so that the protrusions of one mat can be received within the recesses of a similarly configured and adjacently positioned additional mat to interlock the mats together for use.
 2. The mat of claim 1 wherein each protrusion extends by a length that is about the same as either the width or height dimension of the elongated member.
 3. The mat of claim 1 wherein each protrusion is formed of at least 50% of the width and height dimensions of the elongated member so that a stepped arrangement is provided on the second end of the mat with each step configured for receiving a protrusion from the end portion of an adjacent mat to allow interlocking of end to end adjacently arranged mats.
 4. The mat of claim 1 wherein each elongated member has approximately the same width, height and length dimensions and between 4 and 24 elongated members are present in the mat, at least 2 to as many as 12 of which are staggered to provide the protrusions.
 5. The mat of claim 1 wherein between 4 and 10 elongated members are present in the mat with at least 2 to as many as 5 being staggered to provide the protrusions.
 6. The mat of claim 1 wherein each elongated member has width and height dimensions of from about 4″ by about 4″ up to about 12″ by about 12″ and a length of about 1 foot to about 40 feet, with every other elongated component being staggered to provide the protrusions.
 7. The mat of claim 1 wherein the elongated members are made of a solid or layered construction of wood, plastic or elastomeric materials or combinations thereof when a layered construction is provided.
 8. The mat of claim 1 further comprising metal plates configured and dimensioned to be no larger than the sides of the elongated members with the metal plates provided between at least some or all of the elongated members that are adjacently positioned.
 9. The mat of claim 1 wherein each protrusion is formed of the full width and height dimensions of the elongated member so that the protrusions of the first end of the mat are configured to between in the recess between two non-staggered elongated members at the second ends thereof, and with the mat further comprising: a first hole passing through the first end of each protrusion, with the holes being in alignment to form a first bore that is configured to receive a connecting rod that can pass through the holes; and a second hole passing through the second end of each non-staggered elongated member, with the holes being in alignment to form a second bore that is configured to receive the same connecting rod that can pass through the holes; wherein the first and second bores are configured to be in alignment such that when the protrusions of one mat are received in the recesses of another mat, a connecting rod can be passed through each bore to interlock the mats together.
 10. The mat of claim 9 wherein each of the first and second holes passes through a center of the elongated member at the its respective first or second end from one side to the other and wherein some or all of the holes are provided with a sleeve to assist in receiving the connecting rod therein.
 11. The mat of claim 9 wherein at least one or more of the first and second holes includes internal threads to receive a threaded joining member.
 12. The mat of claim 9 wherein the joining members that are solid rods, threaded rods, or a bolting arrangement that includes bolts alone or bolls and nuts.
 13. The mat of claim 4 further comprising an end member that provides a non-staggered end of the mat, wherein the end member comprises an elongated member having a first side that is relatively flat and an opposite side that either has side portions that are configured and dimensioned for positioning between the first end portions that form the protrusions on one end of the mat, or that has side portions that are configured and dimensioned to conform to and extend into the recesses on the opposite side of the mat, so as to square off one end of the mat.
 14. The mat of claim 4 further comprising a metal cap configured and dimensioned to fit the protrusions of the staggered elongated members, the second ends of the non-staggered elongated members, or both, to protect the protrusions and second ends from damage when one mat is being interlocked with the other or when transporting, installing or retrieving the mat, with the metal cap including openings that correspond to the holes of the protrusions or second ends of the elongated members.
 15. A temporary structure comprising a plurality of mats according to claim 1 wherein the mats are connected by the protrusions of one mat received in the recesses of another mat.
 16. A temporary structure comprising a plurality of mats according to claim 4 wherein the mats are connected by the protrusions of one mat received in the recesses of another mat, and a connecting rod that is positioned in each bore to interlock the mats together; wherein the connecting rod is releasably connected to the elongated members so that upon removal the mats can be disengaged from being interlocked.
 17. The temporary structure of claim 16, wherein the connecting rod is a solid cylindrical rod that optionally includes threads.
 18. The temporary structure of claim 16, wherein the connecting rod has a head on one end that is larger than the first or second holes and a threaded opposite end to receive nuts thereon or to engage a threaded holes in one of the protrusions of the staggered elongated members or one of the second ends of the non-staggered elongated members.
 19. The temporary structure of claim 16, wherein the connecting rod is threaded at on opposite ends to receive nuts thereon or to engage threaded holes in the one of the protrusions of the staggered elongated members or one of the second ends of the non-staggered elongated members.
 20. The temporary structure of claim 19, wherein the connecting rod is threaded throughout the entire length of the rod and nuts are provided for each end. 